Substitutes for Potent Greenhouse
Gases
Preface
In recent years, the consumption of potent greenhouse
gases in Denmark has increased, whilst at the same time the
consumption of CFCs, HCFCs and other substances, depleting
the ozone layer, is approaching zero.
Especially the consumption of HFC-substances has
increased. These substances are used as substitutes for CFCs
and HCFCs for certain purposes, especially for refrigeration
and blowing of polyurethane foam. However, it should be
mentioned that more environmentally friendly alternatives
have been introduced, e.g. hydrocarbons in aerosol cans,
cyclopentane for district heating pipes and hydrocarbons,
ammonia and water in various types of refrigeration
systems.
CFCs (halogenated chlorofluorocarbons), HCFCs
(hydrochlorofluorocar-
bons), HFCs (hydrofluorocarbons), PFCs (fluorocarbons) and
SF6 (sulphur hexafluoride) are all artificial substances
which were not to be found in nature until recently.
Furthermore, as these substances are relatively stable,
their lifetime in the atmosphere is long. This applies
particularly to the fully halogenated substances: CFCs, PFCs
and SF6. The CFCs and HCFCs are ozone depleting substances,
which are subjected to an international convention, the
Montreal Protocol, for guarantee of elimination of these
substances. Except essential uses, Danish and EU legislation
has now prohibited the use of CFCs. Additionally, the use of
HCFC is decreasing in Denmark and will be brought to a
complete stop before year 2002. After December 31st 1999,
the erection of new plants using HCFC is forbidden.
Because HFCs, PFCs and SF6 contain neither chlorine nor
bromide, these substances will not contribute to any
depletion of the ozone layer. However, they contribute to
the greenhouse effect. The United Nation Climate Convention
conducted the regulation of greenhouse gases. The substances
have been included in the list of greenhouse gases (in the
Kyoto Protocol) and the countries have to reduce the
emission of them. The substances are regarded as comparable
to carbon dioxide (CO2), methane (CH4) and nitrous oxide
(N2O).
In 1997, Danish consumption of HFC substances amounted to
app. 890 tonnes, where the corresponding amount of SF6 was
app. 13 tonnes. If the entire amount of these substances was
released to the atmosphere, the resulting impact would
correspond to an increased emission of greenhouse gases,
corresponding to app. 1.6 million tonnes of CO2 (the
contribution would be 78% from the HFC substances, 18% from
SF6 and 3% PFC). That corresponds to app. 3% of the Danish
CO2 emission (57.3 million tonnes in 1997). In addition,
some of the substances have a very long life in the
atmosphere.
This it the reason why the Council for Re-use and Less
Polluting Technologies has supported this project
financially.
According to experience from the CFC programme it is
possible to recover some CFC and send it to controlled
destruction. From 1993 to 1996 the refrigeration industry,
for instance, has returned a total amount of 163 tonnes of
CFC refrigerant through the KMO organisation (Danish
refrigeration industy's recovery and recycling scheme). Most
of this has been destroyed and a small amount has been
purified and recycled afterwards. Similarly, it must be
expected that some HFC refrigerants will be returned through
the KMO organisation.
However, the recharge of refrigerant mixtures in the R400
series will involve certain difficulties as the original
concentration of the mixture might have changed.
At an international conference for natural refrigerants held
in September 1996, the Danish Minister of Environment and
Energy, Mr. Svend Auken, proclaimed that an environmental
phase-out strategy would be initiated for HFCs and other
potent greenhouse gases in Denmark within a period of 10
years. At the same time, he asked the Danish Environmental
Protection Agency (the Danish EPA) to investigate how the
phase-out strategy could be carried out and also to initiate
discussions about this topic with industry and the green
organisations. This report forms part of the basis for the
further discussion.
In addition, HFCs, PFCs and SF6 are registered on the Danish
EPA's list of non-desirable substances. It was published as
an official list in 1998 (Environmental Review No. 7, Danish
Environmental Protection Agency, 1998).
In recent years, various technologies have been discussed at
conferences and seminars, in technical magazines and in
daily newspapers. Many questions have been asked about how
to find the most suitable techno-logy that is
environmentally safe and safe to use. Examples are modern
household refrigerators using two kinds of refrigerants,
viz. HFC-134a and hydrocarbon (isobutane).
Such discussions will presumably continue many years from
now. It is not only a discussion between industry on the one
side and green organisations on the other. It is to a high
degree a discussion among people within different industrial
trades and the discussions are often influenced by
commercial considerations.
The Energy Division at Danish Technological Institute (DTI
Energy) is aware that this report might be used as reference
in such discussions. The steering committee, established by
the Danish EPA on the basis of this project, consists of
members representing both industry and green
organisations.
The Danish EPA has assessed that matters related to this
project shall be discussed freely in order to allow the
members of the steering committee and their respective
organisations to contribute with further information. DTI
Energy will then attempt to depict all relevant and factual
information.
However, development continually takes place within the
various technological areas mentioned in this report.
Therefore, some of the information will quickly become
obsolete. Finally, there might be information DTI has no
knowledge of and therefore it has not been mentioned in this
report.